Printing press feed mechanism

Abstract

A device for feeding envelopes or similar work pieces to a printing press or the like utilizes a vacuum chamber mounted on a reciprocably driven roller for removing the lowermost envelope out of a stack of envelopes in a hopper and advancing it to a carrier for conveyance to the printing press. The vacuum is fed to the vacuum drum through an elongated passageway along the axis of the roller and a valve at the input of the vacuum at one end of the roller reciprocates with the roller to open and close the vacuum passageway. Also, a pusher lug is provided to assist in removing heavier stock from the hopper.

I claim: 
     
       1. A system for individually feeding envelopes from a stack of envelopes to a work station, comprising: a hopper for holding a multitude of envelopes in flat stacked relationship with the flap edge of the envelope as the leading edge;   an elongated cylindrical feed roller located under the stacked envelopes in said hopper;   an elongated vacuum passageway along the axis of said feed roller;   a generally cylindrical vacuum drum coaxially mounted on said feed roller for rotational movement therewith in close proximity to the bottom envelope in said hopper, said drum having an interior vacuum chamber in vacuum communication with said roller vacuum passageway and a series of exterior vacuum outlet ports for applying vacuum to the lowermost envelope in the stack;   a vacuum source;   a vacuum source passageway coupling said vacuum source to one end of said roller vacuum passageway;   valve means in said vacuum source passageway operated by said feed roller, said valve means operable between an open condition and a closed condition as said feed roller reciprocably rotates between a first and a second position;   continuously moving carrier means;   means for reciprocably rotating said feed roller and said vacuum drum between a first position and a second position for withdrawing the bottom envelope from said hopper; and   means for delivering each withdrawn envelope from said feed roller to said carrier means.   
     
     
       2. The envelope feeding system as described in claim 1 wherein said means for delivering the withdrawn envelopes to said carrier means includes: feeder wheel means rotatably mounted coaxially on said feed roller alongside said vacuum feed drum; and means for continuously rotating said feeder wheel means in a direction to advance each withdrawn envelope to said carrier means.   
     
     
       3. The envelope feeding system as described in claim 1 further including: a pusher lug for contacting the trailing edge of the bottom envelope in said hopper; and   means linking said pusher lug to said feed roller to reciprocably move said pusher lug for repetitively advancing the bottom envelope toward said carrier as said roller reciprocably rotates between said first and second positions.   
     
     
       4. The envelope feeding system as in claim 2 wherein said vacuum drum vacuum outlet ports include a series of axially spaced circumferentially elongated slots for applying vacuum suction to the withdrawn envelope from the first position to the second position of said vacuum drum. 
     
     
       5. The envelope feeding system as in claim 4 further including arcuate perforated skid plates alongside said feeder wheel means for slidably supporting each withdrawn envelope. 
     
     
       6. The envelope feeding system as in claim 3 wherein said means linking said pusher lug to said feed roller includes: a slider bar;   arm means pivotably attached at one end to the exterior of said vacuum drum and pivotably attached at the other end to said slider bar; and   means adjustably attaching said pusher lug to said slider bar.   
     
     
       7. The envelope feeding system as described in claim 1 wherein said carrier means comprises: a pair of spaced-apart, endless, continuously moving link chains; and   a series of carrier lugs mounted on each of said chains in spaced relation for moving each envelope delivered to the chains.   
     
     
       8. The envelope feeding system as described in claim 7 wherein each carrier lug comprises: a flat base member attached to a link of one of the chains;   an upright post member attached to said base member; and   a finger member pivotably attached to the next adjacent link on said chain for lifting the envelope away from said post member when said carrier chain reaches the end of its forward travel.   
     
     
       9. For use with a hopper containing a stack of envelopes, the envelopes arranged with the flap down and the flap edge as the leading edge and each envelope having a window area between the leading and trailing edges, a system for individually removing the envelopes from the hopper, comprising: an elongated cylindrical feed roller located under the stacked envelopes in the hopper;   a generally cylindrical vacuum drum coaxially mounted on said feed roller for rotational movement therewith in close proximity to the bottom envelope in the hopper, said vacuum drum having an interior vacuum chamber and a series of exterior vacuum outlet ports for applying suction to the bottom envelope in the hopper;   means for reciprocably rotating said feed roller and said vacuum drum between a first position and a second position for withdrawing the bottom envelope from said hopper; and   means for feeding vacuum to said drum chamber for applying suction to the bottom envelope while the drum moves from the first to the second position to pull the bottom envelope downward from the next envelope in the stack such that the edge of the window area of the bottom envelope avoids the edge of the flap of the next envelope in the stack.